Temperature alarm



1959 E. J. WELLS 2,867,186

TEMPERATURE ALARM Filed May 2, 1956 INVENTOR. Ear/ J We/As 66A HOFF5 54 /CA{ 4199:.

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United States Patent C) This invention relates to a temperature alarm device and, more particularly, relates to a device suitable for use as a domestic household appliance which will sound an audible warning when the contents of a pan or the like reach a desired temperature.

Although warning devices have been suggested in the past for household use, they have not been fully satisfactory because they are unduly complicated, or because they are slow to respond, or because they cannot easily be set to various temperatures.

It is an object of the present invention to provide a device for household use which will sound an audible warning when the contents of a pan reach a desired temperature.

Another object of this invention is to provide such a device which may be readily set to any desired temperature within a wide range.

Still another object of this invention is to provide a temperature alarm device wherein a bimetallic strip is employed which is in direct contact with the liquid in a pan whereby there will be substantially no time delay and the warning will be sounded immediately upon the contents of the pan reaching a desired temperature.

Other objects and features of advantage of the invention will be apparent from the balance of the specification.

In the drawings forming part of this application:

Figure 1 is a front view of the device of the present invention.

Figure 2 is a side view of the device of the present invention, partly in section.

Figure 3 is a sectional view on the lines 3--3 of Figure 2.

Turning now to a description of the drawings by reference characters, the device has a frame of generally triangular shape made of heavy wire, having two sides 5 and 7 and a base portion 9. The base portion 9 may be flattened near its center, as at 11, to support a bimetallic strip 13 by means of rivets 15 or other suitable fastening device. Bimetallic strip 13 is well-knownto those skilled in the art, and consists of two metals, one of which, 17, is relatively rapidly expanding, while the other, 19, has relatively low coefficient of expansion. Thus, in the embodiment shown, and referring particularly to Figure 2, as the strip 13 becomes heated, the outer end, 21, will bend downward.

One of the sides 5'is bent back upon itself as at 22 to form a support 23 for a post 25, which in turn holds a bell 27. The opposite side 7 is welded or brazed to the side 5, as at 29, and turned outwardly and flattened as at 31, to form a support for a spring, 33, which has a hammer 35 at the end thereof.

Pivoted for rotation on the post 25 is the dial assembly 37. The dial assembly 37 has a flat face 39 on which suitable indicia can be placed, and a central knob 41, which may be easily grasped by the fingers so that the whole can be turned. The opposite side of the dial assembly has a hub 43, so that it can rotate freely on the post 25. The knob is held in place by a screw or other suitable fastener, 45. The dial assembly 37 is also provided with a cam plate, generally designated 47, and a boss 49. A spring 51 is wound around the hub 43, and one end of the spring fits into a hole in the cam plate,

Patented Jan. 6, 1959 as at 53, while the opposite end 55 bears against the support member 23.

The cam plate, which has been generally designated 47, has a series of teeth, such as at 59 and at 61, which are arranged in the form of a helix. Thus, it will be noted that tooth 59 is considerably closer to the post 25 than the tooth 61. A rod 63 is fastened to the bimetallic strip and extends upwardly between the sides 5 and 7, which serve as a guide and terminates in a pointed end 65.

In assembling the device, the spring 51 is placed over the post 25 and one end is inserted in the dial assembly 37 and the other end is permitted to engage the post, as at 23, and the knob 41 is turned in a clockwise direction for a sufficient number of turns to put some tension on the spring 51, whereupon the dial assembly 37 is pushed in so that the boss 49 will engage near the center of the spring 33 and prevent the device from unwinding. When one desires to use the device, it is only necessary to turn the knob 41 in a clockwise direction and to stop it at any desired point. For instance, in Figure 1, the knob has been stopped at the scald indicia. The device is then placed in a pan of water, soup or the like, and the pan heated. When the contents of the pan reach the desired temperature, the bimetallic strip 13 will pull the rod 63 downward, whereupon the spring 51 will cause the dial assembly 37 to rotate in a counter-clockwise direction, and the boss 49 will strike the spring 33, causing the hammer 35 to strike the bell, thus producing the audible warning.

The device can be reset at any desired time. Thus, if one has turned the dial too far, it may be turned backwards without injuring the device, since the teeth on the cam plate slant in both directions.

Although a preferred embodiment of the invention has been described, it will be obvious to those skilled in the art that many departures can be made from the exact construction shown, without departing from the spirit of this invention.

I claim:

A temperature alarm device comprising: a support consisting essentially of two heavy, wire-like legs and a movable operating rod, a temperature-responsive bimetallic strip supported between the bottoms of said legs and connected to the lower portion of said rod and oriented to increase its downward curvature on the application of heat thereto and thus pull said rod downwardly, one of said legs being bent at its upper end to form a support for a post, the other of said legs being attached to said first leg and flattened to form a support for a flat, springlike member having a hammer at the end thereof, a bell supported on said post, a dial assembly having an inwardly-extending hub rotatable on said post, and carrying indicia and a central knob outwardly thereof, a cam plate having a striking knob also mounted on said hub, a coil spring wound round the hub, one end thereof fitting into a hole in the cam plate and the other end bearing against said post, said spring being put under tension by Winding said knob clockwise, said cam plate having a series of teeth around its periphery arranged in the form of a helix, said operating rod having a pointed upper end engageable with said teeth so that, when pulled down by said bimetallic strip, said coil spring is released to cause said carn to rotate in counterclockwise direction causing said striking knob to strike said spring-like member thus causing said hammer to strike the bell to produce an audible warning.

References Cited in the file of this patent lJNITED STATES PATENTS 2,563,877 Sfreddo Aug. 14, 1951 

